1. Field of the Invention
The present invention relates to an optical fiber device, and more specifically to an array optical subassembly for an array optical active component that has good alignment between the optical active component and the optical fiber cable.
2. Description of Related Art
To establish an optical fiber communication system requires many and complex optical devices and fiber cables. In addition, a coupling technique for the optical devices and the fiber cables is very important to keep the light signal steady in the communication system.
According to U.S. Pat. No. 6,510,262, ('262) a Z-axis alignment of the fiber, lens and source arrays has been proposed to improve coupling quality among the fiber, lines and source arrays. With reference to FIG. 7 (FIG. 2 in the '262 patent wherein the only difference is in the numerals), the alignment includes a separation-setting member (83), a lens array (81), a chip (82) mounted on a metallic member (84), guide pins (85), a connector (87) with fiber cable (80), and a receptacle (86).
To increase accuracy of alignment between the chip (82) and the lens array (81), the lens array (81) is first mounted on the separation-setting member (83) and then the guide pins (85) are connected through the metallic member (84), the guide pins (85), the receptacle (86) and the connector (87). Therefore, the metallic member (84), the guide pins (85), receptacle (86) and the connector (87) are combined together by use of the guide pins (85), but alignment process of the chip (82), the lens array (81) and the fiber cable (80) is complex. One active alignment process is required in mounting the lens array (81) on the separation-setting member (83). In addition, the lens array (81) may become undesirably heated while the lens array (81) is being adhered on the separation-setting member (83). As the lens array (81) is generally made of plastic, such heating may negatively effect the curvature thereof, and thus the stability of light signals transmitted will be impaired. Thus, satisfactory micro-level of alignment in the '262 patent is not achievable.
Further, U.S. Pat. No. 6,547,454, ('454), discloses another coupling device for optical active components and the lens array. With reference to FIG. 8 (FIG. 4 in the '454 patent and wherein the only difference is in the numerals), the optical active component (8) and the lens array (8′) are formed as multiple alignment keys (not numbered) by a semiconductor fabricating process. The alignment keys include multiple fine grains (7) and grooves (9). For example, the multiple grains (7) are formed on a surface of the optical active component (8) and the fine grooves (9) are formed on a surface of the lens array (8′) corresponding to the fine grains (7). When the optical active component (8) and the lens array (8′) are assembled together, the alignment keys increase the accuracy of the alignment between the optical active components and lens array. The '454 patent uses the alignment keys in the semiconductor fabricating process so the alignment between the lens array and optical active components can be successfully achieved at micro-level. However, the lens array and the optical active components must be processed by the semiconductor fabricating process to form the micro-level alignment keys and thus the '454 patent requires a complex fabricating process.
The present invention provides an array optical subassembly having a high accuracy of alignment and a simple assembly process.